The sodium sulfobromophthalein (Bromsulphalein) test (BSP) in the nonjaundiced patient remains today as one of the best and most sensitive indicators of liver dysfunction. It is not, however, useful in the differential diagnosis of jaundice since bilirubin competes with the dye for removal by the liver.
When the dye is injected intravenously, most of it is taken up by the liver cells, stored, conjugated, and finally excreted in the bile. An abnormal retention of sulfobromophthalein represents, therefore, a disturbance of one or more of these functions. A decreased blood flow to the liver will also lead to an increased retention of the dye. An insignificant quantity of the sulfobromophthalein is absorbed from the small intestine and transported back to the liver—the so-called enterohepatic circulation.
The technique is as follows: 5 mg of dye per kilogram of body weight is injected intravenously. In the calculation of the number of cubic centimeters
Charm RM. Sulfobromophthalein. JAMA. 1967;202(10):979. doi:10.1001/jama.1967.03130230105021